1. Field: The instant invention relates to processes for forming cellular glass pellets from individual solid waste glass particles.
2. Prior Art: Various techniques have been practiced for producing small particles of foamed glass, including the crushing of large slabs of foamed glass. Such techniques have produced foam glass particles with a porous surface and a substantial number of open cells. It has been found that when such foam glass particles have been used as a lightweight aggregate for addition to various matrices, that such pellets absorb a substantial quantity of the matrix material and further present a very extended surface which may be attacked by alkali, moisture and other elements which are corrosive to glass.
In U.S. Pat. No. 3,321,414, a process is disclosed which involves granulating glass to form particles of about 0.5 to about two millimeters in diameter. Fine particles are admixed with an alkali metal silicate solution and an organic substance and fed onto a granulating device, such as a pelletizing pan. The granular particles discharged from the granulating device have a diameter within a range of about 0.5 to about two millimeters. These granulates are then fed to a kiln for firing after being coated with a release agent such as bentonite.
In U.S. Pat. No. 3,532,480 of D'Eustachio, a process is set forth for forming sheets of cellulated glass by admixing of small particles, that is, particles less than about 200 mesh, in the presence of a binder, such as sodium silicate and a foaming agent such as carbon black to form small pellets. These pellets are then dried and a parting agent or release agent such as alumina, in the form of a hydrate, thereafter added. The amount of parting agent is limited so that upon foaming the parting agent prevents the pellets from adhering to the walls of the kiln or each other until after the foaming has been initiated but permits the pellets to become sufficiently sticky so that the pellets when discharged from the kiln and subjected to a compaction force distort, agglomerate and form a unitary mass or sheet.